1. Field of the Invention
The present invention relates to toner cleaning systems in electrophotographic printing devices for removing residual toner from device components, and, more particularly, to an agitation system for improving toner transport through the cleaning system.
2. Description of the Related Art
A printing device, such as a laser printer or copier, using the electrophotographic process includes a photosensitive member, such as a photoconductive drum, which is uniformly charged over the surface thereof. A latent image is electrostatically formed by selectively exposing the uniformly charged surface of the photosensitive member. Microscopic marking particles, known as toner, are applied to the electrostatic latent image, and subsequently transferred to the media intended to receive the final, permanent image. The toner image is fixed to the media by the application of heat and pressure in a fuser.
The design and implementation of an electrophotographic process in a printing device requires the handling of toner through a variety of different systems, in order to deliver a solid image to the media. The surfaces of the various components contacting toner within the different systems often require cleaning to remove residual amounts of toner resulting from film splitting, residual charges on the surfaces and the general characteristics of the toner. If not removed, the residual toner on component surfaces can adversely affect the quality of subsequent print jobs.
Current applications are known to use a scraping blade located against a surface to be cleaned in an electrophotographic apparatus, to peel the toner from the belt, roll, or other surface. Another known method to clean surfaces in an electrophotographic apparatus, is to utilize a cleaning web which is located and indexed against the rotating surface, to remove the toner from the surface. A cleaning web system consists of a supply spool, take up spool, nip forming roll and one or more idle rolls. The web material is brought into contact with the electrophotographic component via a spring loaded biasing roll, and the web is driven during the machine operation in order to remove contamination from the surface it contacts. Although both concepts work to some degree, the use of a cleaning web tends to require a large amount of hardware, which is more costly than a blade-type system.
However, the implementation of a blade cleaning system is also difficult, due at least in part to the properties of the toner itself. As the toner is removed from the EP component, the toner must be moved some distance to a waste container provided for receiving and containing the toner. The qualities of the toner generally make the driving of the toner difficult, due to the tendency of toner to adhere to any surface it contacts within the cleaning system, as well as for the toner to adhere to itself in clumps. Therefore, the toner must be driven from the point of contact with the cleaning system, through the system to an auger and then into the waste container in which it is received.
Cleaning systems are known to use the force generated by incoming toner, to push toner through the cleaner system housing and into an augering system. Difficulties can be encountered in a toner driven system, in that the toner may be pushed in unintended directions, as a result of the tendency of the toner to cling to surfaces and clump to itself. Toner leakage can occur, or toner may bypass the cleaning system all together. Additionally, due to the tendency of the toner to clump, the system must be able to handle large toner dumps that may occur if a large clump reaches the auger. If designed to handle a large toner dump, the system may be over designed for normal routine operation. If not designed to handle a large enough toner dump, leakage and other problems can occur. Further, the system must be designed to handle the back pressure generated by toner already in the housing and to handle stress on the components generated by the force of the toner.
What is needed is an improved system and apparatus for moving the toner from the point at which the toner is removed from a printer component to the auger, which positively transports the toner toward the waste container.
The present invention provides a simple, yet reliable mechanism for transporting toner through a toner cleaning system.
The invention comprises, in one form thereof, a toner cleaning apparatus for removing toner from a toner receiving surface of a component of a printing device. The toner cleaning apparatus has a toner separator operating against the component surface, to dislodge toner particles therefrom, a toner receptacle for collecting the dislodged toner particles, and an auger for transporting dislodged toner particles to the toner receptacle. A vibration plate is disposed for receiving toner particles dislodged by the toner separator and for directing dislodged toner particles to the auger. The vibration plate includes a receiving edge and a discharge edge, the discharge edge having first lengths thereof engaged by the auger, and second lengths thereof spaced from the auger.
The invention comprises, in another form thereof, a method for cleaning toner from a component of a printing device, comprising providing a toner separating device and an auger; providing a vibration plate having a receiving edge and a discharge edge, and providing the discharge edge of the vibration plate with first portions and second portions, the second portions being nearer to the receiving edge than are the first portions; operating the separator against the component to dislodge toner from the component; receiving dislodged toner on the vibration plate near the receiving edge; vibrating the vibration plate through engagement of the first portions by the auger; discharging toner into the auger along the second portions of the discharge edge of the vibration plate.
The invention comprises, in still another form thereof, a printing device with a printing station including a printhead having a toner receiving component. A toner separator operates against the component surface, to dislodge toner particles therefrom. A toner receptacle collects the dislodged toner particles, and an auger transports dislodged toner particles to the toner receptacle. A vibration plate is disposed for receiving toner particles dislodged by the toner separator, and for directing dislodged toner particles to the auger. The vibration plate includes a receiving edge and a discharge edge, the discharge edge having first lengths thereof engaged by the auger, and second lengths thereof spaced from the auger.
An advantage of the present invention is providing a mechanically simple and operationally reliable mechanism for positively transporting toner through a toner cleaning apparatus.
Another advantage is providing a transport mechanism that tends to break up and dislodge toner clumps, and minimizes the tendency of toner to adhere to the surface of the toner transporting mechanism.
Yet another advantage is providing a toner cleaning apparatus that reduces toner dumps, allowing reduced sizing of the apparatus, and reduced installation cost for the apparatus.